"Shortly after Buddy died, Boo showed signs of heart issues. We think his heart literally broke when Buddy left us. He hung on and gave us over a year. But it looks like it was his time, and I’m sure it was a most joyous moment for them when they saw each other in heaven," they wrote.

Known for his teddy-bear-like appearance, Boo had his own line of plush toys modeled after him, which are produced by toy maker Gund. He also was the subject of four picture books.